Separation membrane module

ABSTRACT

A separation membrane module may decrease a bending load applied to a support member supporting ends of tubular separation membranes and omission of a seal member between the outer circumferential surface of the support member and the inner circumferential surface of a housing. The separation membrane module may include a tubular housing, tubular separation membranes arranged in a longitudinal direction of the housing, end tubes connected to lower ends of the tubular separation membranes, a support box supporting the end tubes, and a backpressure chamber below the support box. The tubular separation membranes may be in communication with a support box collection chamber. A nozzle disposed on the support box may extract permeated fluid. A chamber and the backpressure chamber are in communication via a gap between the support box outer circumferential surface and the inner circumferential surface. The chamber and backpressure chamber have substantially the same pressure.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation based on U.S. application Ser.No. 17/128,585, filed Dec. 21, 2020, and published as US 202110170339A1, which was bypass continuation of international applicationPCT/JP2019/025129, filed on Jun. 25, 2019, claiming the benefit of thefiling date of Japanese Appl. No. 2018-121043, filed on Jun. 26, 2018,the content of each of which is incorporated by reference.

DESCRIPTION OF THE RELATED ART Technical Field

The present invention relates to a separation membrane module that isused to separate a component part from a fluid such as a solution ormixed gas.

Background Art

A known apparatus for separating a component in a solution or mixed gasis a separation membrane module. A tubular separation membrane that isused in the separation membrane module includes a tubular porous supportand a porous separation membrane that is disposed on the outercircumferential surface of the support and that is composed of, forexample, zeolite. Known methods of separating a specific component froma fluid such as a solution or mixed gas include a method of vaporizingand separating the specific component by bringing the fluid of thesolution into a side (an outer surface) of a separation membrane elementand decreasing the pressure of the other side (an inner surface), amethod of separating the specific component by vaporizing the solutioninto gas, bringing the gas into the separation membrane, and decreasingthe pressure of a non-contact surface, and a method of separating thespecific component by bringing the pressurized mixed gas into theseparation membrane.

JP2016-155093 A (particularly in FIG. 6(a)) discloses that a separationmembrane module includes a tubular housing that is disposed in thevertical direction and tubular separation membranes that are arranged inthe vertical direction in the housing, end tubes are connected to lowerend portions of the tubular separation membranes, the end tubes protrudefrom the upper surface of a support plate that is installed such thatthe support plate crosses the housing, insertion holes are formed on theupper surface of the support plate, and the end tubes are inserted intothe insertion holes.

Gas that has permeated through the tubular separation membranes flowsinto an outflow chamber below the support plate and is retrieved fromthe outlet chamber via an outlet.

In a structure in JP2016-155093A in which the end tubes that areconnected to the lower ends of the tubular separation membranes areinserted into the insertion holes of the support plate, and the endtubes are supported by a support box, pressure in the outlet chamberbelow the support plate is lower than pressure in a fluid-processingchamber above the support plate, and a large bending load is applied tothe support plate.

The structure in JP2016-155093A needs sufficient sealing between theouter circumferential surface of the support plate and the innercircumferential surface of the housing in order to prevent gas in afluid-processing chamber above the support plate from passing through aspace between the outer circumferential surface of the support plate andthe inner circumferential surface of the housing and leaking to theoutlet chamber.

In the case where the modules are installed in series, the structure inJP2016-155093A also needs a pipe that is interposed between the modules.

It is an object of the present invention to provide a separationmembrane module that enables a bending load that is applied to a supportthat supports ends of tubular separation membranes to be decreased, thatenables a seal between the outer circumferential surface of the supportand the inner circumferential surface of a housing to be omitted, andthat enables a bundle of the membranes to be installed in series in thesingle module without using a pipe.

SUMMARY OF THE INVENTION

The separation membrane module of the present invention comprises: atubular housing; and tubular separation membranes that are arranged inthe housing in a longitudinal direction of the housing, a fluid to beprocessed flowing through a fluid-processing chamber inside the housingin a direction from one end toward another end of the chamber, the fluidthat has permeated through the tubular separation membranes beingretrieved via the tubular separation membranes, and an end portion ofeach tubular separation membrane being supported by a support that isinstalled in the housing such that the support extends to cross thehousing, wherein the separation membrane module further comprises: acollection chamber that is defined in the support and that is incommunication with an inside of each of the tubular separationmembranes; a retrieving member that retrieves the fluid in thecollection chamber to outside of the housing; a backpressure chamberthat is defined between the support and an end portion of the housing;and a communication portion that communicates an inside of thebackpressure chamber to the fluid-processing chamber.

In one aspect of the present invention, the communication portion is agap between an outer circumferential surface of the support and an innercircumferential surface of the housing.

In one aspect of the present invention, a plurality of tubularseparation membrane units are disposed in the housing, each unitincluding the support and the tubular separation membranes connectedthereto; and the collection chamber of the tubular separation membraneunit nearest to the backpressure chamber is communicated to thecollection chamber of the other tubular separation membrane unit via aconnection.

In one aspect of the present invention, the connection is a nozzle thatextends from the support.

In one aspect of the present invention, the nozzle extends from eachsupport, and the nozzle of the tubular separation membrane unit and thenozzle of the tubular separation membrane unit adjacent thereto arecoupled with each other.

In one aspect of the present invention, the separation membrane modulefurther comprises a bearing that bears the nozzle on the innercircumferential surface of the housing.

In one aspect of the present invention, the bearing includes a rollingelement that is in contact with the inner circumferential surface of thehousing and that is capable of rolling.

In one aspect of the present invention, the rolling element iselastically pressed against the inner circumferential surface of thehousing, e.g., by an elastic member.

In one aspect of the present invention, a post, or otherdeformation-preventing structure, that prevents the support fromdeforming is disposed in the collection chamber.

In one aspect of the present invention, the collection chamber isdefined by two or more parts.

In a separation membrane module according to the present invention, thebackpressure chamber is defined between the support and an end portionof the housing, the backpressure chamber is in communication with thefluid-processing chamber, and pressure in the backpressure chamber andpressure in the fluid-processing chamber are substantially the same. Forthis reason, a bending load that is applied to the support due to thepressure of a fluid to be processed is eliminated or very small.According to the present invention, it is not necessary to dispose aseal between the outer circumferential surface of the support and theinner circumferential surface of the backpressure chamber. Theseparation membrane module according to the present invention has thecollection chamber in which a component part in the fluid to beprocessed that has permeated through the tubular separation membranes iscollected. Accordingly, bundles can be installed in series in the singlemodule, and there is no need for a pipe that is needed for an existingmodule. Accordingly, costs can be reduced, installation can befacilitated, and maintenance can be facilitated.

BRIEF DESCRIPTION OF DRAWINGS

A more complete appreciation of the invention and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIG. 1 is a sectional view of a separation membrane module according toan embodiment taken along the axis of a housing;

FIG. 2 is a sectional view taken along line II-II in FIG. 1;

FIG. 3 is a sectional view taken along line III-III in FIG. 1;

FIG. 4 is an enlarged sectional view of end tubes and a support box;

FIG. 5 is a sectional view taken along the axis of the housing of aseparation membrane module according to another embodiment;

FIG. 6 is an enlarged view of a part in FIG. 5;

FIG. 7 is a sectional view taken along line VII-VII in FIG. 6;

FIG. 8 is a sectional view illustrating another support mechanism;

FIG. 9 is a sectional view of a part of a separation membrane moduleaccording to another embodiment taken along the axis of the housing;

FIG. 10 is a sectional view illustrating of another form of a part inFIG. 4;

FIG. 11a is a sectional view illustrating another form for FIG. 6 andFIG. 7;

FIG. 11b is a sectional view taken along line XIb-XIb in FIG. 11 a:

FIG. 12 illustrates a longitudinal section of a support box thatincludes a deformation-preventing structure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A separation membrane module according to an embodiment of the presentinvention will be described with reference to FIG. 1 to FIG. 4.

A separation membrane module 1 includes a housing 2 that has acylindrical tube shape a cylinder axis direction of which coincides withthe vertical direction, tubular separation membranes 3 that are arrangedparallel to the axis of the housing 2, a support box 5 that is disposedin a lower portion in the housing 2 and that serves as a support, abottom cover 6A that is mounted on the lower end of the housing 2, a topcover 6B that is mounted on the upper end, a first baffle (a baffleplate) 7 and a second baffle (a baffle plate) 8 that are parallel to thesupport box 5 and that are disposed in the lower portion and an upperportion in the housing 2, and so on. The first baffle 7 is disposedabove the support box 5.

According to the embodiment, flanges 2 a, 2 b, 6 b, and 6 c that extendoutward are disposed on the lower end and the upper end of the housing 2and the outer edges of the bottom cover 6A and the top cover 6B, andthese are secured with bolts (not illustrated).

A gap through which gas can flow is formed between the outercircumferential surface of the support box 5 and the innercircumferential surface of the housing 2. The support box 5 is placed onsupport 2 t that project from the inner circumferential surface of thehousing 2. A backpressure chamber 16 is between the support box 5 andthe bottom cover 6A. The backpressure chamber 16 is in communicationwith a chamber 11 above the support box 5 via the gap between the outercircumferential surface of the support box 5 and the innercircumferential surface of the housing 2.

According to the embodiment, end tubes 4 are coupled with the lower endsof the tubular separation membranes 3. End plugs 20 are coupled with theupper ends of the tubular separation membranes 3. In FIG. 1 to FIG. 3,the number of the tubular separation membranes illustrated is 7.However, a large number of the tubular separation membranes are actuallyprovided as illustrated in FIG. 4.

In FIG. 1, each tubular separation membrane 3 has a single body.However, multiple tubular separation membranes 3, for example, twotubular separation membranes 3 may be coupled with a joint tubeinterposed therebetween.

An inlet 9 for a fluid to be processed is formed through the outercircumferential surface of a lower portion of the housing 2, and anoutlet 10 for the fluid to be processed is formed through the outercircumferential surface of the upper portion. The inlet 9 is formed soas to face the chamber 11 between the support box 5 and the first baffle7. The outlet 10 is formed so as to face a chamber 12 above the secondbaffle 8. A fluid-processing chamber 13 is defined between the baffles 7and 8. The fluid-processing chamber is also referred to below as a mainchamber.

Rods 14 extend upward from the support box 5 in a bottom portion, andthe baffles 7 and 8 are supported by the rods 14. In FIG. 2 and FIG. 3,the number of the rods 14 disposed is 4, but is not limited thereto andmay be, for example, 2 to 3 or 5 or more. An external thread is formedon the lower end of each rod 14 and is screwed along an internal threadof the support box 5. The baffles 7 and 8 are supported at predeterminedheights by using sheath tubes 14A and 14B (FIG. 4) into which the rods14 are fitted. The sheath tubes 14A are disposed between the support box5 and the baffle 7. The sheath tubes 14B are disposed between thebaffles 7 and 8. The baffle 8 is placed on the upper end surface of eachsheath tube 14B and is secured by using a nut that is screwed at theupper end of each rod 14. A method of securing the baffles is notlimited thereto, and rods 14A′ and 14B′ may be coupled and secured byusing screws as in a rod 14′ illustrated in FIG. 10. The number of thebaffles is not limited by the embodiment, and three or more baffles, forexample, may be used.

Seals such as O-rings, V-packings, or C-rings may be interposed betweenthe outer circumferential surfaces of the baffles 7 and 8 and the innercircumferential surface of the housing 2 such that gas does notpreferentially flow along an outer circumferential portion of thehousing 2.

The baffles 7 and 8 have circular through-holes 7 a and 8 a into whichthe tubular separation membranes 3 are inserted, and coupling bodies ofthe tubular separation membranes 3, the end tubes 4, and the end plugs20 are inserted in the through-holes 7 a and 8 a. The inner diameters ofthe through-holes 7 a and 5 a are larger than the diameters (the outerdiameters) of the tubular separation membranes 3, the end tubes 4, andthe end plugs 20, and gaps are formed between the inner circumferentialsurfaces of the through-holes 7 a and 8 a and the end tubes 4 andbetween the inner circumferential surfaces of the through-holes 7 a and8 a and the outer circumferential surfaces of the end plugs 20 over theentire circumference.

As illustrated in FIG. 1 and FIG. 4, the support box 5 includes a boxbody that has a top 5 t, a bottom 5 s, and a side surface 5 u and has acollection chamber 5 v for gas therein. A nozzle 5 n through which thegas in the collection chamber 5 v flows out is formed through the bottom5 s. An extraction nozzle 6 n that is coupled with the nozzle 5 n with,for example, a flange joint and that serves as an extraction structureis formed so as to extend through the bottom cover 6A.

In the collection chamber 5 v, a deformation-preventing that preventsthe support box 5 from deforming may be disposed. When differences inpressure between the main chamber 13 and the collection chamber 5 v,between the chamber 11 and the collection chamber 5 v, and between thebackpressure chamber 16 and the collection chamber 5 v are large, thedeformation-preventing can prevent the support box 5 from deforming.When the differences in pressure are 10 times or more although thisdepends on the size and throughput of the module, and thedeformation-preventing structure is provided, the support box 5 can beeffectively prevented from deforming.

The shape of the deformation-preventing structure may be any shapeprovided that the support box 5 can be prevented from deforming but ispreferably a shape that connects the top 5 t and the bottom 5 s to eachother such that the top 5 t and the bottom 5 s can be prevented fromdeforming. The deformation-preventing structure may be an elasticstructure such as a columnar member or a spring. Thedeformation-preventing member is preferably a columnar member becausethe columnar member is typically easy to obtain. A section of thecolumnar member may be a solid section or a hollow section. A hollowdeformation-preventing structure is lightweight and can effectivelyprevent compressive deformation. A solid deformation-preventingstructure is easy to obtain. A sectional shape of the columnar membermay be circular or rectangular. A circular shape is preferable becauseof ease of obtaining.

The deformation-preventing structure may be provided such that holes areformed on the lower surface of the top 5 t and the upper surface of thebottom 5 s, the upper end of the deformation-preventing structure isengaged with the hole of the top 5 t, and the lower end of thedeformation-preventing structure is engaged with the hole of the bottom5 s. An internal thread may be formed on an inner circumferentialsurface around a hole, an external thread may be formed on the outercircumferential surface of an end portion of a rod-like or tubulardeformation-preventing structure, and the deformation-preventingstructure may be screwed in the hole.

The support box 5 may include two or more parts in order to readilyinstall the deformation-preventing structure. For example, the top 5 tor the bottom 5 s may be removable, or a portion near the top 5 t and aportion near the bottom 5 s may be equally divided. The two or moreparts may be integrally formed by welding, may be integrally formed byfastening from the outside with flanges provided, or may be screwedtogether with an internal thread formed on the side surface in adirection from the top 5 t toward the bottom 5 s. In the case where thetwo or more parts are not welded, a gasket or an O-ring is preferablyprovided to ensure airtightness.

FIG. 12 illustrates an example of the support box that includes thedeformation-preventing structures. A support box 5R is obtained bycoupling an upper half body 5J and a lower half body 5L. A flange Sethat is disposed on the lower edge of the upper half body 5J and aflange 5 f that is disposed on the upper edge of the lower half body 5Lare stacked and coupled with each other. Deformation-preventingstructures 5 r are disposed between the top 5 t and the bottom 5 s. Theother components of the support box 5R are the same as those of thesupport box 5 illustrated in FIG. 1, and like reference signs representlike components.

The projections 2 t on which the support box 5 is disposed as describedabove may be omitted. For example, a support (not illustrated) mayextend upward from the bottom cover 6A, the support box 5 may besupported by the support in order to increase the strength of thesupport box 5. The support is preferably between the top 5 t and thebottom 5 s so as not to completely cover large holes 5 c, and the singlesupport or multiple supports may be provided.

Insertion holes 5 a in which the lower ends of the end tubes 4 that arecoupled with the tubular separation membranes 3 are inserted are formedon the top 5 t of the support box 5. Each insertion hole 5 a has acolumnar shape and extends from the upper surface of the support box 5to an intermediate position in a thickness direction. The bottoms of theinsertion holes 5 a face the collection chamber 5 v with small holes 5 band large holes 5 c interposed therebetween (or there may be only thesmall holes Sb without the large holes Sc).

Gaskets (not illustrated) are interposed between the lower end surfacesof the end tubes 4 and the bottoms of the insertion holes Sa.Alternatively, O-rings (not illustrated) are interposed between the sidesurfaces of the end tubes 4 and side surfaces around the insertion holes5 a.

As illustrated in FIG. 4, tube holes 4 a of the end tubes 4 are incommunication with the collection chamber 5 v with the small holes 5 band the large holes Sc interposed therebetween. Joints between the endtubes 4 and the tubular separation membranes 3 are sealed by usinggaskets, O-rings, or thermal shrink tubes.

The end plugs 20 are coupled with the upper ends of the tubularseparation membranes 3. The end plugs 20 have a columnar shape or ashape obtained by cutting the columnar shape and seal the upper ends ofthe tubular separation membranes 3. Small-diameter portions that areinserted in the tubular separation membranes 3 are disposed at the lowerends of the end plugs 20. Spaces between the end plugs 20 and thetubular separation membranes 3 are sealed by gaskets or O-rings. Thespaces between the end plugs 20 and the tubular separation membranes 3may be sealed by using thermal shrink tubes although an illustrationthereof is omitted.

According to the present invention, the end tubes 4 and the support box5 may be disposed near the upper ends of the tubular separationmembranes 3, and the end plugs 20 may be disposed near the lower ends ofthe tubular separation membranes 3.

In the separation membrane module 1, the fluid to be processed isintroduced into the chamber 11 of the housing 2 via the inlet 9, passesthrough gaps between inner circumferential surfaces around through-holes7 a of the baffle 7 and the outer circumferential surfaces of the endtubes 4, flows into the main chamber 13, passes through the main chamber13, subsequently passes through gaps between the through-holes 8 a ofthe baffle 8 and the end plugs 20, and flows out to the chamber 12.While the fluid to be processed flows through the main chamber 13, acomponent part therein permeates through the tubular separationmembranes 3 and is extracted from inside of the tubular separationmembranes 3 via the collection chamber 5 v and the nozzles 5 n and 6 n.The fluid that has not permeated flows out of the outlet 10 to outsidethe separation membrane module 1.

According to the embodiment, the backpressure chamber 16 and the chamber11 are in communication with each other via the gap between the outercircumferential surface of the support box 5 and the innercircumferential surface of the housing 2, and there is no difference inpressure between the chambers, or the difference is very small.Accordingly, a bending load that is applied to the support box 5 is verysmall. In addition, there is no need for a part that seals the spacebetween the outer circumferential surface of the support box 5 and theinner circumferential surface of the housing 2.

The direction of flow in the main chamber 13 and the direction of flowin the tubular separation membranes 3 may be the same or may beopposite, and the inlet 9 and the outlet 10 for the fluid to beprocessed may be replaced with each other.

As illustrated in FIG. 1, the separation membrane module 1 may be usedwith the top cover 6B facing upward or may be used with the bottom cover6A facing upward. The separation membrane module 1 may be used so as tobe installed sideways such that a direction in which the bottom cover 6Aand the top cover 6B are connected to each other is substantiallyhorizontal.

According to the embodiment, a large number of the tubular separationmembranes 3 are installed so as to be parallel to each other, and amembrane area is large. Accordingly, membrane separation is efficientlyperformed.

According to the embodiment, the end tubes 4 and the end plugs 20 thatare coupled with the upper and lower ends of the tubular separationmembranes 3 are inserted in the through-holes 7 a and 8 a of the baffles7 and 8. For this reason, even when the tubular separation membranes 3vibrate or swing, and the end tubes 4 and the end plugs 20 come intocontact with the inner circumferential surfaces of the through-holes 7 aand 8 a, zeolite membranes are not damaged, and operation can stablycontinue for a long period of time.

Another embodiment of the present invention will be described withreference to FIG. 5.

As for a separation membrane module 1A according to the embodiment,tubular separation membrane units 30 and 31 are disposed in the housing2. The tubular separation membrane unit 30 includes the support box 5,the end tubes 4, the tubular separation membranes 3, the end plugs 20,the baffles 7 and 8, and the rods 14 in FIG. 1 to FIG. 4.

The tubular separation membrane unit 31 is almost the same as thetubular separation membrane unit 30 but differs in that a communicationnozzle 5 i that serves as a connection extends upward from the center ofthe top 5 t of the support box 5. The upper end of the communicationnozzle 5 i extends to a position higher than that of the baffle 8 of thetubular separation membrane unit 31, and the upper end thereof iscoupled with the lower end of the nozzle 5 n of the tubular separationmembrane unit 30 by using, for example, a screw joint or a flange joint.

Gaps through which an upper chamber and a lower chamber are incommunication with each other and gas can flow are formed between theouter circumferential surfaces of the support boxes 5 of the tubularseparation membrane units 30 and 31 and the inner circumferentialsurface of the housing 2.

The other components of the separation membrane module 1A are the sameas those of the separation membrane module 1, and like reference signsrepresent like components. Also, in the separation membrane module 1A,the fluid to be processed flows into the housing 2 via the inlet 9, aspecific component permeates through the tubular separation membranes 3,and a non-permeated fluid flows out via the outlet 10. Gas that haspermeated through the tubular separation membranes 3 of the lowertubular separation membrane unit 31 flows into the collection chamber 5v in the support box 5 of the tubular separation membrane unit 31 and isextracted via the nozzles 5 n and 5 i. Gas that has permeated throughthe tubular separation membranes 3 of the upper tubular separationmembrane unit 30 flows into the collection chamber 5 v of the supportbox 5 of the tubular separation membrane unit 30, flows into thecollection chamber 5 v in the support box 5 of the lower tubularseparation membrane unit 31 via the nozzles 5 n and 5 i, and isextracted via the nozzles 5 n and 6 n.

As for the separation membrane module 1A, the length of the housing 2can be increased, and the tubular separation membrane units can bedisposed in the housing 2. In FIG. 5, the single tubular separationmembrane unit 30 and the single tubular separation membrane unit 31 areillustrated. However, the tubular separation membrane units 31 may becoupled with each other in up-and-down multistage arrangement, and thetubular separation membrane unit 30 may be coupled with the top portion.Alternatively, the tubular separation membrane units 31 may be coupledwith each other in up-and-down multistage arrangement, and the nozzle 5i at the top stage may be sealed by using, for example, a cap or aflange. This enables components to be the units that have the samestructure and enables costs to be reduced.

In the case where the tubular separation membrane units are installed inthe vertical direction, the upper tubular separation membrane unit issupported by the lower tubular separation membrane unit. In this case,however, a bearing that prevents the tubular separation membrane unitsfrom inclining or swinging from side to side may be provided. FIG. 6 andFIG. 7 illustrate an example thereof in which bearings 40 extend inradial directions from one or both of the nozzles 5 n and 5 i (both inthe case of FIG. 6). The bearings 40 include rods 41, base ends of whichare mounted on the nozzles 5 n and 5 i, ball holders 42 on ends of therods 41, and rolling structures such as balls 43 that are held by theball holders 42 and that are capable of rolling. The rods 41 includeelastic structures such as springs (not illustrated), and the ballholders 42 are urged in the radial directions. Consequently, the balls43 are pressed against the inner circumferential surface of the housing2, and the nozzles 5 n and 5 i are held at the position of the axis ofthe housing 2. When the tubular separation membrane units 30 and 31 aretaken out or put into the housing 2, the balls 43 roll along the innercircumferential surface of the housing 2. FIG. 7 illustrates a sectiontaken along line VII-VII in FIG. 6. FIG. 6 illustrates a section takenalong line VI-VI in FIG. 7.

In FIG. 6 and FIG. 7, the balls 43 are used. However, rollers may beused.

In FIG. 6 and FIG. 7, the base ends of the rods 41 are directly mountedon the nozzles 5 n and 5 i. However, as illustrated in FIG. 11a and FIG.11b , a tubular boss 40B may be mounted on the nozzle 5 n (or 5 i), andthe rods 41 may be mounted on the boss 40B. An example of a method ofsecuring the boss 40B to the nozzle 5 n (or 5 i) involves forming atapped hole in the boss 40B and securing the boss 40B by using a screw40N from the outside of the boss 40B. A flange portion and a jointportion that are installed on a nozzle end portion are preferablyremovable by, for example, screwing in order to facilitate mounting andremoving of the boss 40B.

In the case where the separation membrane module 1 is installed sidewayssuch that the direction in which the bottom cover 6A and the top cover6B are connected to each other is substantially horizontal, a dispersionplate or the support box 5 of a bundle (a combination of, for example,the separation membranes, the end tubes, and the support box) that isinserted in the housing 2 comes into contact with the inner wall of thehousing 2 in some cases. The heavier the bundle, the more the frictionalforce of the contact. This makes it difficult to push the bundle thereinin some cases.

In view of this, as illustrated in FIG. 8, a base plate 45 may bemounted on the nozzle 5 n (or 5 i), and the rods 41 may be mounted onthe base plate 45. The rods 41 may be omitted, and the ball holders 42may be directly disposed on the base plate 45. The thicknesses of therods that support the weight of the bundle can be decreased bydecreasing the lengths of the rods 41. Even when the bundle rotatesduring insertion of the bundle into the housing 2, the balls can alwaysbe located between the bundle and the housing 2 by increasing the numberof the ball holders 42, and this facilitates the insertion.

According to the present invention, a tubular body 50 that surrounds thetubular separation membrane unit 31 may be disposed so as to be alongthe inner circumferential surface of the housing 2, a baffle 51 may besupported on the upper end of the tubular body 50, the nozzle 5 i may beinserted in a center hole Sla of the baffle 51, and the upper portion ofthe nozzle 5 i may be supported by the baffle 51 as in a separationmembrane module 1B in FIG. 9. The outer circumferential surface of thesupport box 5 and the outer circumferential surface of the baffle 51 areslightly spaced from or are in contact with the inner circumferentialsurface of the housing 2. The baffle 51 has a large number of openings51 b that extend from the top to the bottom thereof. A layer composed ofa slidable material such as fluorine resin is preferably disposed on theouter circumferential surfaces of the support box 5 and the baffle 51 inorder to decrease resistance when the bundle is inserted. The lower endof the tubular body 50 is in contact with the upper surface of thebaffle 7.

The other components in FIG. 9 are the same as those in FIG. 5, and likereference signs represent like components.

According to the embodiment described above, the chambers 11 and 16 arein communication with each other via the gap between the outercircumferential surface of the support and the inner circumferentialsurface of the housing. A communication portion such as a pipe via whichthe chambers 11 and 16 are in communication with each other may bedisposed in the housing 2. Alternatively, the top 5 t and the bottom 5 smay be coupled with each other by using a single pipe or pipes.

Preferred materials of the end tubes 4, the end plugs 20, and thetubular separation membranes 3 that are included in a separationmembrane module according to the present invention will now bedescribed.

Examples of the materials of the end tubes 4 and the end plugs 20include a material through which the fluid does not permeate such asmetal or ceramics, but are not limited thereto. The materials of thebaffles 7, 8, and 51, and a joint tube 17 are typically a metal materialsuch as stainless steel but are not particularly limited provided thatthe material has resistance against a supply or permeation component andheat resistance in separation conditions and can be replaced withanother material such as a resin material depending on use.

Each tubular separation membrane 3 preferably includes a tubular poroussupport and a zeolite membrane that serves as an inorganic separationmembrane that is formed on the outer circumferential surface of theporous support. As for the material of the tubular porous support, aninorganic porous support composed of a sintered metal body or a sinteredceramic body containing silica, α-alumina, γ-alumina, mullite, zirconia,titania, yttria, silicon nitride, or silicon carbide is taken as anexample. Among these, an inorganic porous support containing at leastone selected from alumina, silica, and mullite. The average diameter ofnarrow holes on the surface of the porous support is not particularlylimited but is preferably controlled and is in the range of typically0.02 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm ormore, and typically 20 μm or less, preferably 10 μm or less, morepreferably 5 μm or less.

Zeolite is crystalized on the surface of the porous support and thezeolite membrane is formed.

The main zeolite of which the zeolite membrane is composed includeszeolite that typically has an oxygen 6-to-10-membered ring structure andpreferably includes zeolite that has an oxygen 6-to-8-membered ringstructure.

The value of n of the zeolite that has an oxygen n-membered ringsdescribed herein represents the maximum number of oxygen atoms in thenarrow holes composed of T elements and oxygen for forming a zeoliteframework. For example, in the case where there are narrow holes ofoxygen 12-membered rings and oxygen 8-membered rings as in MOR zeolite,this is regarded as zeolite of oxygen 12-membered rings.

Examples of the zeolite that has an oxygen 6-to-10-membered ringstructure include AEI, AEL, AFG, ANA, BRE, CAS, CDO, CHA, DAC, DDR, DOH,EAB, EPI, ESV, EUO, FAR, FRA, FER, GIS, GIU, GOO, HEU, IMF, ITE, ITH,KFI, LEV, LIO, LOS, LTN, MAR, MEP, MER, MEL, MFI, MFS, MON, MSO, MTF,MTN, MTT, MWW, NAT, NES, NON, PAU, PHI, RHO, RRO, RTE, RTH, RUT, SGT,SOD, STF, STI, STT, TER, TOL, TON, TSC, TUN, UFI, VNI, VSV, WEI, andYUG.

The zeolite membrane may be a membrane composed of zeolite alone, amembrane that is formed by dispersing powder of the zeolite in a bindersuch as a polymer, or a zeolite membrane composite obtained by bondingzeolite to various kinds of supports in a membrane form. A part of thezeolite membrane may contain an amorphous component.

The thickness of the zeolite membrane is not particularly limited but istypically 0.1 μm or more, preferably 0.6 μm or more, more preferably 1.0μm or more, and is typically 1(0) μm or less, preferably 60 μm or less,more preferably 20 μm or less.

According to the present invention, however, a tubular separationmembrane that includes a separation membrane other than the zeolitemembrane may be used.

The outer diameter of each tubular separation membrane 3 is preferably 3mm or more, more preferably 6 mm or more, further preferably 10 mm ormore, and is preferably 20 mm or less, more preferably 18 mm or less,further preferably 16 mm or less. In some cases where the outer diameteris too small, the tubular separation membrane has insufficient strengthand is easy to break. If the outer diameter is too large, then themembrane area per module decreases.

The length of a portion of each tubular separation membrane 3 that iscovered by the zeolite membrane is preferably 20 cm or more and ispreferably 200 cm or less.

In a separation membrane module according to the present invention, thetubular separation membranes may be single-tube membranes or multi-tubemembranes, 1 to 3000 tubular separation membranes, particularly, 50 to2000 tubular separation membranes are typically provided, and thetubular separation membranes are preferably arranged such that theminimum distance therebetween is 1 mm to 10 mm. The size of the housingand the number of the tubular separation membranes are appropriatelychanged depending on the amount of the fluid to be processed. Thetubular separation membranes may not be coupled by using the joint tube17. In the description with reference to the drawings, the separationmembrane module 1 is vertically installed but may be used with theseparation membrane module 1 installed sideways or diagonally.

The fluid to be processed that is a target for separation orconcentration in a separation membrane module according to the presentinvention is not particularly limited provided that the fluid is a gasor liquid mixture that contains components that can be separated orconcentrated by using the separation membranes and may be any mixture.The separation membrane module, however, is preferably used for a gasmixture.

A separation or concentration method called a pervaporation method, or avapor permeation method can be used for the separation or theconcentration. The pervaporation method is a separation or concentrationmethod in which a liquid mixture is introduced into each separationmembrane as it is and can facilitate a process including the separationor the concentration.

In the case where the mixture to be separated or concentrated accordingto the present invention is a gas mixture containing components,examples of the gas mixture include a mixture that contains at least onecomponent selected from the group consisting of carbon dioxide, oxygen,nitrogen, hydrogen, methane, ethane, ethylene, propane, propylene,normal butane, isobutane, 1-butene, 2-butene, isobutene, aromaticcompounds such as toluene, sulfur hexafluoride, helium, carbon monoxide,nitrogen monoxide, and water. A gas component that has high permeance inmixtures containing these gas components permeates through eachseparation membrane and is separated. A gas component that has lowpermeance is concentrated toward a supply gas.

Separation membrane modules according to the present invention can becoupled with each other and used depending on the amount of the fluid,the target degree of the separation or the target degree of theconcentration. In the case where the amount of the fluid is large, or inthe case where the target degree of the separation or the target degreeof the concentration is high, and the process cannot be performed by asingle module, a pipe is preferably connected and used such that thefluid that exits the outlet enters the entrance of another module. Thetarget degree of the separation or the target degree of theconcentration can be achieved by additional coupling of module dependingon the degree of the separation or the degree of the concentration.

Separation membrane modules according to the present invention may beinstalled in parallel, the fluid may be split, and the gas may besupplied. In this case, modules can be installed in series with therespective modules that are installed in parallel. In the case where themodules are installed in parallel and in series, the amount of thesupply gas decreases in the series direction, and linear velocitydecreases. Accordingly, the number of the modules that are installed inparallel is preferably decreased to ensure appropriate linear velocity.

In the case where the modules are arranged in series, the component thathas permeated through the modules may be discharged from the respectivemodules or may be discharged after the component is collected with themodules coupled.

The present invention is described in detail by using a specific aspect.However, it is clear for a person skilled in the art that variousmodifications can be made without departing from the intention and scopeof the present invention.

REFERENCE SIGNS LIST

-   -   1, 1A, 1B separation membrane module    -   2 housing    -   2 a, 2 b flange    -   2 t support    -   3 tubular separation membrane    -   4 end tube    -   4 a tube hole    -   5, 5R support box (support)    -   5J upper half body    -   5L lower half body    -   5 a insertion hole    -   5 b small hole    -   5 c large hole    -   5 i, 5 n nozzle    -   5 r deformation-preventing member    -   5 s bottom    -   5 t top    -   5 u side surface    -   5 v collection chamber    -   6A bottom cover    -   6B top cover    -   6 b, 6 c flange    -   6 n nozzle    -   7,8 baffle    -   7 a, 8 a through-hole    -   9 inlet    -   10 outlet    -   11, 12 chamber    -   13 main chamber (fluid-processing chamber)    -   14 rod    -   14A, 14B sheath tube    -   16 backpressure chamber    -   20 end plug    -   30,31 tubular separation membrane unit    -   40 bearing    -   41 rod    -   42 ball holder    -   43 ball    -   45 base plate    -   17 coupling rod    -   50 tubular body    -   51 baffle    -   51 a center hole    -   51 b opening

1: A separation membrane module, comprising: a tubular housing having afirst housing end and a second housing end, and comprising a first and asecond tubular separation membrane extending longitudinally from thefirst housing end to the second housing end within the tubular housing;a top cover, longitudinally outermost at the first housing end; a bottomcover, longitudinally outermost at the second housing end; a collectionchamber, within the tubular housing at the second housing end, incommunication with an inside of each of the tubular separationmembranes, and comprising an outlet to outside of the tubular housing; asupport box, at the second housing end longitudinally beyond thecollection chamber, defining an end of each tubular separation membrane,the support box resting on a support arranged within the housing; and abackpressure chamber, within the tubular housing at the second housingend, defined between the bottom cover and the support box, wherein afluid to be processed flowing through a fluid-processing chamber insidethe housing in a direction from one end toward another end of thechamber, the fluid having permeated through the tubular separationmembranes being retrieved via the tubular separation membranes, andwherein insides of the backpressure chamber and the fluid-processingchamber are in fluid communication. 2: The module of claim 1, whereinthe communication comprises a gap between an outer circumferentialsurface of the support and an inner circumferential surface of thehousing. 3: The module of claim 2, comprising three or more tubularseparation membrane units disposed in the tubular housing, each unitcomprising the support and the tubular separation membranes, the tubularseparation membranes being connected to the support, and wherein thecollection chamber of the tubular separation membrane unit nearest tothe backpressure chamber is communicated to the collection chamber ofthe other tubular separation membrane unit via a connection. 4: Themodule of claim 3, wherein the connection comprises a nozzle thatextends from the support. 5: The module of claim 4, wherein at least oneof the nozzle extends from each support, and wherein a first nozzle ofthe first tubular separation membrane unit and a second nozzle of asecond tubular separation membrane unit, adjacent to the first nozzle,are coupled with each other. 6: The module of claim 1, furthercomprising: a bearing configured to bear the nozzle on the innercircumferential surface of the housing. 7: The module of claim 5,wherein the bearing comprises a ball and/or roller that is in contactwith the inner circumferential surface of the housing and that iscapable of rolling. 8: The module of claim 7, wherein the ball and/orroller is elastically pressed against the inner circumferential surface.9: The module of claim 1, wherein in the collection chamber comprises,disposed in the collection chamber, posts configured to preventdeformation of the support. 10: The module of claim 1, wherein thecollection chamber is defined by two or more parts. 11: The module ofclaim 1, wherein the collection chamber is defined by a support boxcomprising a top or a bottom that is removable. 12: The module of claim1, wherein the collection chamber is defined by a support box comprisinga portion near the top and a portion near the bottom, divided from eachother. 13: The module of claim 12, wherein the collection chamber isdefined by an upper half body and the lower half body that are equallydivided.